Hydraulic transmission mechanism



Feb.2, 1194a. J. T. CORRIGAN 2,1913% HYDRAULIC TRANSMISSION MECHANISMFiled June 6, 1938 INVENTOR.

- ATTORNEYS.

Patented Feb. 20,1940 I UNITED, T E

PATEN OFFICE g 2,191,340] I HYDRAULICTTRANSMISSIONltiEGHANISM. John T.'Corrigan, Newport, R. I. Application June 6, 1938,. Serial. No. 212,115teams} (a. 192-41)" 7 This invention relates to a power control andbrake mechanism; and has for one of its-objects to provide a fluiddevice for transmitting power from one rotatable member to another, andfor 5 controlling, varying or preventing relative rotation between saidmembers. 7

Another object of the invention is to provide a v device which may beinterposed as a unit between a rotatable drive member and a rotatablemem- 10 her to be driven for effecting-a transfer of power between thetwo rotatable members in-a smooth,

efiicient and practically noiseless manner, and will dispense with theuse of a mechanical clutch device and manually operable shift gears 5Another object of the invention is the provision of an improved fluiddevice for effecting connecticn' and disconnection to a power meansof arotatable element to be driven, and also for controlling and/or changingthe speed of the driven element whereby any speed ratio between thedriven and driving elementsmay be obtained.

Another object of the invention is the provision of a combined fluidclutch and transmission for use with a power means, such as the powerplant of a motor vehiclefor connecting andcontrolling the transfer ofpower and relative rotation between the driving and driven elementsWithout tween a driving and a driven member, and for ef.' testing adirect mechanical connectionxof saidi members when rotation at the samespeed is established. l

mechanism simultaneously with the direct "me chanical connection. of thedriving and driven members after rotation of the two members at 45 thesame speed'is est'ablished. i

With these and other objects in view,ithe invention consists of. certainnovel features of construction, as will be more fully described, andparticularly pointed out in the appended claims.

In the accompanying drawing: 1 Fig. 1 is a perspective view of acombined fluid power control and transmission device embodying thepresent invention; v 25 Fig. 2 is a longitudinal central sectional view4' Another object of the inventionis the render 'ing ineffective of thefluid power transmission of the combined fluid power control andtransmission mechanismshown in Fig. 1;

Fig. '3 is a transverse sectional view taken substantially on the line3-3 of Fig. 2 looking in the direction of the arrows, showing thepump-15 inggears in operating-relation therein;

Fig. 4 is, a fragmentary perspective view of a portion of the driveshaft from the power plant for the pump gear mechanism, showing thegraduated ports for relieving pressure in the apparatus;

Fig. 5' is a fragmentary perspective View of a portion of the slidecontrol valve showing the annular groove for regulating fluid flowthrough the ports. in the drive-shaft;

Fig.6 'isa transverse sectional view taken on the line B-Ei.of Fig. 2;and I Fig. 7-isi a transverse sectional view on the line. l sofFig. 2showing the power driving shaft in direct-driving connection with thedriven member. a r

I In the operation of various mechanisms'wherein a rotatable element isto be driven at variable speeds or intermittently connected to arotatable power means, such as for example, in the. power drivenmechanism employed in the propulsion of a motor vehicle, it is customaryto employ a mechanical clutchidevice. and a power transmission =unitincorporating manually shiftable gears, the unit being interposedbetween the power plant of the automobile and the propeller shaft fordriving the rear Wheels of thevehicle, and by shifting certain of thegears of the train to vary the speed of the propellershaft'andconsequent- Plythat-of the rear wheels driven thereby; and in order toeliminate the various objections accompanying the use of suchprior'power transmis-. sion mechanism, among which are the loss inpower. and fuel during the interval of shifting gears, the tendency ofnoisyengagement of gears 40 during. shifting, stallingof the motorthrough sudden overloading by improper coordination of the clutching andgear shifting operations, a com.- binedpower control and transmissiondevice of the. fluid type is provided in which the driven membercomprises a: hollow closed cylindrical casing divided by an arcuatepartition concentric therewith into :two separate, interc'ommuniw eatingcompartments; in one of which is disposed a pump gear mechanism; and inorder to control the flow of fluid. which is forced bya pump gearmechanism into av pressure chamber, and to regulate the pressure exertedby the pumped "fluid therein. in oppositiori'to the path of travel'offth'e pump gears whereby'theyfare re- '55 strained in their movementto be either held against rotation or controlled in their speed so as tocause the casing to be rotated at any desired rate of speed by a driveshaft, there is also provided valve means concentric with one of thepump gears and the drive shaft and reciprocable within the bore of thedrive shaft by means of a sleeve slidably mounted on the drive shaftexteriorly of the casing; and movable with the valve means is a passagethereon adapted to be moved into and out of coincidence with a pluralityof circumferentially spaced graduated ports in the hollow wall portionof the drive shaft. These ports form communication for fluid with aplurality of radial fluid passages in one of the pump gears wherebyfluid may be regulated in its escape from the fluid pressure chamber andcaused to be discharged into the fluid supply at the inlet side of thepump gear mechanism, this control of the pressure exerted by the pumpedfluid in the fluid chamber providing an effective and accurate means forcontrolling the speed of rotation of the driven casing in relation tothat of the drive shaft or for holding the driving and the drivenelements locked together for rotation at the same speed and to obtaindirect mechanical drive of the elements, which last feature is obtainedby providing a set of teeth on the sleeve for engagement with a set ofteeth on the casing; and the following is a more detailed description ofthe present embodiment of this invention, illustrating the preferredmeans by which these advantageous results may be accomplished:

With reference to the drawing, Ill designates a closed hollowcylindrical metal casing which in the illustrated embodiment constitutesthe driven member of my power transmission device, and is shown in Figs.1 and 2 as being of a generally drum-like construction having anintegral end wall H, and a removable end wall 12 formed with a centralhub l3 and secured to the casing in an oil tight joint by bolts M. :Theend wall H is provided with a central hub 15 which is axially alignedwith the hub E3 of the removable end wall and may be suitably connectedto one end of the rotatable element to be driven (not shown), such asfor example, the usual propeller shaft ofa motor vehicle that isconnected at its other end with the usual differential mechanism fordriving the rear wheels of the vehicle. As shown in Fig. 3, an arcuatepartition 16 concentric with the casing 10 and within the same dividesthe casing into separate compartments H and [8 that are filled with oilor other hy-' draulic fluid.

Carried within the casing I is a pump gear mechanism arranged in thecompartment l8 for the purpose of building up pressure on the fluid, andthis comprises a pump gear 20 which is loosely mounted for rotation upona stub shaft 2| fixed to the end wall H of the casing. The gear 20meshes with a similar pump gear 22 within the compartment I8 andpositively driven by being keyed, as indicated by keys 23 and 24,

.to the tubular end portion of a drive shaft 25 which projects laterallyof the partition l6 through the removable end wall I2 and thecompartment it into an axial bore 26 in the hub for the rotatablesupport of the terminal end of the shaft 25. The main body portion ofthe drive shaft 25 extends outwardly through the removable end wall l2exteriorly thereof and has rotative bearing in a stuffing box 21 thereinof conventional design maintained oil tight by the packing nut 28, whilethe exterior distal end extremity oi the drive shaft 25 may be connectedin a known manner to a suitable source 01'' power, such as the powerplant of a motor vehicle.

A slide valve device is associated with the above described gear pumpmechanism and the drive shaft 25 for effecting connection or rotation ofthe casing NJ at variable speeds by the drive shaft, and this consistsof a Valve rod manually, controlled in a manner hereinafter describedreclprocably mounted for sliding movement within a longitudinal bore allof the power drive shaft 25.

Extending circumferentially around an inter- 'mediate section of thevalve rod 3E9 which is disposed withinthe casing it is an annular groove33 for establishing communication with a plurality of graduated ports 34in the tubular wall portion of the drive shaft 25 and this groove 33,upon manual shifting movement of the valve rod 30 to slide the same, isbrought into a position in registry with the ports. As illustrated inFigs. 3 and 4, the ports 3d are disposed at equally spaced positionsaround the periphery of the shaft 25, and they may be formed of suitableshape-to provide the desired tapering or cut-oil action on the pumpedfluid when closed by reciprocation of the manually controlled valve rod36. As shown in the present embodiment, the ports 3 3 each are ofdiamond-shaped formation and, in conjunction with a corresponding numberof radial conduits or passages 35 in the pump gear 22, they form freefiQlW fluid communication between the arcuate pockets or chambers 36 and3! in the casing it which extend laterally of the pump gear compartmentH8 at opposite sides of the pumping zone of the pump gears 20 and 22 inthe path of travel of the pumped fluid at either side thereof, wherebyin the opened position of the valve rod St] the oil or hydraulio'fluidthat has been forced up into the upper pocket or fluid pressure chamber36 during rotation of the pump gears 20 and 22 can pass to or escape outof the fluid pressure chamber 36 through one or more of the passages 35of the gear 22 to be discharged into the lower pocket 3'! on the inletside of the pump gears where this efiiuent may intermix with the fluidsupply. The conduits 35 each consist of a cylindrical bore, the exteriorend opening of which preferably is disposed at the portion of thecircumference of the gear 22 that connects two adjacent teeth. 1

A pressure relief valve device is provided having a bore 60communicating at one end with the fluid pressure chamber 36 and openingat its other end into an enlarged cylindrical bore 6! which is providedwith outlet passage 62 communicating with the chamber W. A ball valvemember 63 in the bore 51 engages at its bottom surface against aspherical valve seat 6 1 at the inner end of the bore 50 and is heldagainst the seat by a spring 65. A set screw tit is threaded into thetop end of the bore 6i, and the bottom end of the screw is of steppedformation to provide an annular portion 6'! adapted to engage the upperend of the spring 65 for adjusting the opening pressure of the ball 63and a pin extension 68 co-axial with the screw. Thus, the ball 63 willrise and be moved off the valve seat 64 by the fluid to relieve thefluid pressure within the chamber 36 when the pin til is withdrawn fromengagement with the ball 63 and the pressure of the fluid exceeds thatproduced by the spring 65to seat the ball 63. To get maximum load. ofthe 'device'the ball 63 may be locked in its. seat by screwing down theset screw 66 sufliciently until the end of the pin 68 engages the topsurface of the ball.

In order to provide a means whereby the valve rod 30 may belongitudinally reciprocated in the hollow portion of thedrive shaft25,and shifting movement of the valve rod accomplisheito control thespeed of the casing ill with respect to the drive shaft 25, a slidingsleeve lll is'provided which is mounted on the drive shaft 25 and thesleeve is attached to the valve rod 30 by means of apin ll extendingcross-wise thereof arranged for longitudinal sliding movement in a pairof elongated slots 42 formed in the opposite side wall portions of thehollew end portion of. the drive shaft 25. The sleeve all is arrangedfor longitudinal sliding movement along the drive shaft 25 and ispiloted during such movement by the'splines A l which provide a positivedrive of the sleeve ill and the gear carried at one end thereof, thepurpose of which will be presently described. Shifting of the slidingsleeve lll is In order to provide a direct drive of the casing ill bythe drive shaft 25 after the casing has been brought up to synchronousspeed with the drive shaft, there is provided a vmechanical clutcharrangement and is'shown as consisting of.

an annular recess 56 formed in the end face of the hub l3 of theremovable end wall member 52, and a pluralityof teeth 5| formed in theinner peripheral face of the hub l3 bounding the sides of this recess,the leading side-face of each of'the teeth at being formed with an innersurfacelil lying in a radial plane and an adjoining surface'l't'inclined to the surface 'lllin advance thereof to be initiallyengaged laterally by the teeth of the gear ill upon continuedlongitudinal movement of' the sliding'sleeve .58 to the right of Fig. 2'after the fluid by-pass ports 34 have been entirely cut off by the valverod 36 during previous movement in the same direction for placing thefluid in the fluid chamber 36 under its maximum pressure. The surfaceill is so arranged that when engaged by the gear teeth 45, the sleeveand the casing make interlocking connection and prevent the danger ofthrowing out of engagement of the member should the casing turnat afaster speed than the drive shaft 25.

The operation of the device will be apparent from the foregoingdescription and is as follows: When the valve rodfill is in theposition.

of the casing Ill. This action takes place when the power transmissionunit is in an idling position so that there will be nodriving-connection ormovement of the vehicle. 7 I a In order to connectthedrive shaft 25 into driving engagement with the-casingill theslidvalve rod 30 is controlled by, sliding the splined sleeve 40 by theusual gear shift lever of the vehicle (not shown) in which movement ofthe valve rod 3t towards the right gradually cuts off flow of oilthrough the graduated ports at and the fluid passages 35 in the gear 22,thus progressively increasing the speed of. the vehicle of rotation ofthe casing and consequently as oil flow between the pockets 36 and 3'!is restricted by closing of the valve 3!), pressure is increased in theupper pocket 36 in the upward travel of the fluid therein in oppositionto the path of movement of the pump gears 28 and 22, which action inturn increases pressure thereon to re sist the turning of the gearsconsequently sets up a torque to cause rotation of the transmissioncasing Hi. This turning of the casing ill increases in speed until thevalve 38 has'been com.-

pletely closed, thereby preventing lay-passing of the oil through theports 34 and the passages in the gear 22,'thus controlling or preventingrotation'of the pump gears 20 and 22'which upon being unable to furtherforce oil intothe upper pocket 35, thus drives the transmission casingaround in synchronism with the speed of the i drive shaft 25. However,in order to preclude a possible slippage of the power shaft 25 and thecasing ll} upon reaching synchronous speed due to leakage of the fluid,a mechanical coupling of the drive shaft 25 with the casing is obtainedupon continued motion to the right of Fig. 2 of the sliding sleeve 48which will cause they teeth of the gear 45 to mesh with the teeth oftheir).- ternal gear 5! whereby a direct drive connection results withthe casing ill, the rotation of which will be clockwise in the directionof the arrow as viewed in Fig. 7. 1 It will thus be apparent in view ofthe foregoing construction that the speeds of the drive ing v'alve rod30. is manuallyshifted to the-right and driven members may be contrelledat destood that such devices are well known and may be constructedin'various manners, such as for example, by the employment of a train ofgears for coupling the propeller shaft with the diiferen tial, andhaving a reverse gear shiftable with respect to the partsassociatedtherewith to effect rotation of the differential andrearwheels of the motor vehicle in the opposite direction to therotation of the casing Ill and the shaft 25 indivalve rod 30 is manuallymoved to the left of Fig. 2, and with respect to the drive shaft 25.

cated in'Figs. 3 and 7, when the position of the When the valve rod 30is thus moved the cir-- cumferentialgroove 33 therein will control orcut off passage of fluid through the ports 1% to the fluid passages 35of thegearto cause rotation of the casing lil at the speed differentialexisting between the driven and driving members, and at 'thetrain.Shifting movement'of the valve rod 3!! tothe right of-Fig. 2 then willdisconnect the reverse gear and establish connection of the propellershaft with the casing for forward movement of the vehicle under thedirect control valve.

The foregoing description is directed solely towards the constructionillustrated, but it is to be understood that the privilege is reservedof resorting to all the mechanical changes to which the device issusceptible, the invention being defined and limited only by the termsof the appended claims.

Having thus described the invention, what is claimed as new and desiredto secure by Letters Patent is:

1. In a device of the class described, a hollow closed cylindricalcasing containing fluid, an arcuate partition member within the casingconcentric therewith forming two separate intercommunicatingcompartments, a drive shaft having a hollow end portion extending intothe casing through one of the compartments, the portion of the shaftwithin the compartment being provided with a plurality ofcircumferentially spaced graduated ports around the periphery thereof,intermeshing pump gears in one compartment, one of said gears beingoperatively connected with the drive shaft, means for connecting thecasing to the other gear, pockets in the casing associated with the pumpgear compartment at opposite sides thereof and spaced above and belowthe entrance and discharge passages of the pump gears, passages in oneof said pump gears forming fluid communication between the two pockets,and speed controlling valve means slidable within the drive shaft andone gear adapted to be operated for controlling the flow of fluidbetween the two pockets whereby the pressure of the fluid as it iscarried upwardly into the upper pocket during rotation of the gears willact in opposition to the path of movement of the gears whereby they maybe held against or controlled in rotation to cause the casing to rotatewith the drive shaft.

2. In a device of the class described, a hollow closed cylindricalcasing containing fluid, an arcuate partition member within the casingconcentric therewith forming two separate intercommunicatingcompartments, 2. drive shaft having a hollow end portion extending intothe casing through one of the compartments, the portion of the shaftwithin the compartment being provided with a plurality ofcircumferentially spaced graduated ports around the periphery thereof,intermeshing pump gears in one compartment, one of said gears beingoperatively connected with the drive shaft, means for connecting thecasing to the other gear, pockets in the casing associated with the pumpgear compartment at opposite sides thereof and spaced above and belowthe entrance and discharge passages of the pump gears, passages in oneof said pump gears forming fluid communication between the two pockets,and speed controlling valve means slidable within the drive shaft andone gear adapted to be operated for controlling the flow of fluidbetween the two pockets whereby the pressure of the fluid as it iscarried upwardly into the upper pocket during rotation of the gears willact in opposition to the path of movement of the gears whereby they maybe held against or controlled in rotation to cause the casing to rotatewith the drive shaft, said speed controlling valve means comprising avalve member reciprocable within, the hollow end portion of the driveshaft and provided with an annular circumferential groove adapted toregister with the ports in said drive shaft upon selected slidingmovement of said valve rod.

3. In a device of the class described, a hollow closed cylindricalcasing containing fluid, an, arcuate partition member within the casingconcentric therewith forming two separate intercommunicatingcompartments, a drive shaft having a hollow end portion extending intothe casing through one of the compartments, the portion of the shaftwithin, the compartment being provided with a plurality ofcircumierentially spaced graduated ports around the periphery thereof,intermeshing pump gears in one compartment, one of said gears beingoperatively connected with the drive shaft, means for connecting thecasing to the other gear, pockets in the casing associated with the pumpgear compartment at opposite sides thereof and spaced above and belowthe entrance and discharge passages of the pump gears, said drive gearprovided with a plurality of radial passages having a cylindrical boreopen at one end between a pair of teeth, and speed controlling valvemeans slidable within the drive shaft and one gear adapted to beoperated for controlling the flow of fluid between the two pocketswhereby the pressure of the fluid asit is carried upwardly into theupper pocket during rotation of the gears will act in opposition to thepath of movement of the gears whereby they may be held against orcontrolled in rotation to cause the casing to rotate with the driveshaft.

4. In a device of the class described, a hollow closed cylindricalcasing containing fluid, an arcuate partition member within the casingconcentric therewith forming two separate intercommunicatingcompartments, a drive shaft having a hollow end portion extending intothe casing through one of the compartments, the portion of the shaftwithin the compartment being provided with a plurality ofcircumferentially spaced graduated ports around the periphery thereof,intermeshing pump gears in one compartment, one of said gears beingoperatively connected with the drive shaft, means for connecting thecasing to the other gear, pockets in the casing associated with the pumpgear compartment at opposite sides thereof and spaced above and belowthe entrance and discharge passages of the pump gears, passages in oneof said pump gears forming fluid communication between the two pockets,speed controlling valve means slidable within the drive shaft and onegear adapted to be operated for controlling the flow of fluid betweenthe two pockets whereby the pressure of the fluid as it is carriedupwardly into the upper pocket during rotation of the gears will act inopposition to the path of movement of the gears whereby they may be heldagainst or controlled in rotation to cause the casing to rotate with thedrive shaft, said speed controlling valve means comprising a valvemember reciprocable within the hollow end portion of the drive shaft andprovided with an annular circumferential groove adapted to register withthe ports in said drive shaft upon selected sliding movement of saidvalve rod, and means for moving said reciprocable valve member toposition the annular groove thereon into and out of coincidence with thegraduated ports in the drive shaft.

5. A variable fluid transmission device comprising a rotatable drivingmember, a rotatable casing to be driven at various speeds by said thesupport is idle, being circulated by said pump driving member, saidcasing being divided into two communicating compartments, one of whichcontains fluid and forms a supply reservoir therefor, intermeshing pumpgears in the other compartment, one of said pump gears being operativelyconnected to said driving member for rotation therewith, means forconnecting the easing to the other of said pump gears, a chamber in awall of said pump gear compartment opening toward the same into whichfluid is pumped during normal rotation of said pump gears by saiddriving member and retained therein under pressure during rotation ofsaid casing, liquid conveying passages in one of said pump gearsarranged to effect delivery of streams of fluid under pressure from saidchamber into the source of fluid supply at the inlet zone of said pumpgears, valve means operative upon manual movement to various positionsto establish a communication through which fluid under pressure isdischarged from said chamber through said passages to the inlet zone ofsaid pump gears, and to effect a reduction in pressure of the fluid insaid chamber, said pump gears being subject to the opposing pressure ofthe pumped fluid in said chamber as determined by the posi- 6. In adevice of the class described, in com-,

bination, a hollow driving member, a support constituting the drivenmember and rotatable about the same axis as the said driving member, apair of intermeshing fluid pumping elements,- one of said elements beingfixedly connected with the driving member for rotation therewith, theother of said pump elements being carried by the support for rotationwith respect thereto and for bodily rotation therewith, a wall member onthe support housing said gears and having a portion spaced therefrom toform a fluid receiving chamber between the said pump elements, theperipheries of the oppositely disposed portions of the said pumpelements that approach and enter into meshing engagement with each otherconstituting portions of the walls of said chamber, there being radialpassages leading through one of said pump elements and the said drivingmember to constitute fluid outlets from said chamber, the fluid when thedriving member is rotated and elements into said chamber and from thechamer through said outlets, there being graduated ports in'the drivingmember communicating with the said radial passages, and means slidablewithin the said hollow driving member for controlling the flow of fluidthrough said outlets and cause pressure to be increased upon the trappedfluid as fluid is forced into said chamber dur-' ing rotation of saidpump elements whereby the pressure of the trapped fluid will act'tooppose the rotation of said pump elements whereby they will be heldagainst or controlled in rotation to cause the support to rotate withthe driving member.

7. In a device of the class described, a hollow closed casing containingfluid, an arcuate partition member withinthecasing concentric therewithand dividing the easing into two separate inter-communicatingcompartments, one of which serves as a fluid supply chamber and theother providing a recess constituting a housing for the pump gears, adriving shaft concentric with the casing and rotatable relative thereto,said shaft having a, hollow end portion extending into the casing andthrough said recess, a

plurality of graduated ports in the hollow por-' oppositely disposedportions of the gears that approach and intermesh with each other,radial passages in said drive gear for registry with said ports duringrotation of said gear by the driving shaft to constitute fluid outletsfrom said chamber, the fluid when the driving shaft is rotated and thecasing is idle being circulated by the said gears into said chamber andfrom the chamber through said outlets and ports, and a valve deviceslidable within the hollow portion of said shaft to be manually operatedat will for controlling the flow of fluid through said outlets to trapthe fluid in said chamber to cause the pressure of the fluid to beincreased upon the fluid thus trapped during rotation of the gearswhereby the pressure of the trapped fluid will act to resist the normalpumping movement of the gears whereby they may be held against orcontrolled in their rotation to cause the casing to rotate with saiddriving shaft.

JOHN T. CORRIGAN.

